When news surfaced recently that a "leopard seal" had hauled out on the shores of Queensland's North Stradbroke Island, the story piqued our interest. Australia's Sunshine Coast falls well outside the home range of these Antarctic predators, so this seemed like a case of mistaken identity. After speaking with several experts, we can confirm that this animal is most definitely not a leopard seal. It is, however, very far from home indeed.
WATCH: Seal sighted on North Stradbroke Island, south of Point Lookout. #9News pic.twitter.com/0Nprx4Vod2
— Nine News Queensland (@9NewsQueensland) June 24, 2017
It turns out the unlikely visitor isn't even a true seal at all. According to Scripps Institution of Oceanography marine biologist Dr Doug Krause, who has done extensive work on leopard seals with the National Oceanic and Atmospheric Administration's Antarctic Ecosystem Research Division, the animal is actually a member of another pinniped family: the otariids (sea lions and fur seals).
Those big front flippers are the biggest giveaway: unlike leopard seals and their kin, who schooch around on their blubbery bellies, otariids are able to prop themselves up on "all fours" to walk on dry land.
"The footage isn't good enough for me to identify it to species, but my best guess is that this is a large male Australian fur seal," says Krause. "It is not normal for them to be so far north in Australia, so that explains why local folks didn't recognise it."
These animals (genus Arctocephalus) usually spend their time around the Bass Strait, parts of Tasmania and southern Victoria – all of which lie well over 1,000 miles from North Stradbroke Island, where the misidentified pinniped caught some afternoon sun late last week.
Meanwhile, staff at Queensland's Sea Life Aquarium suggest an ID that would put the fur seal even farther off from its known range. They suspect this individual is a subantarctic fur seal (Arctocephalus tropicalis).
"Subantarctic fur seals are found in the Australian region, but the important breeding sites are on Macquarie Island," says the team. That's nearly 2,000 miles from the North Stradbroke beach.
The animal's colouration – its white chest, muzzle and face – does seem to line up well with that of subantarctic fur seals, and if the hunch is correct, last week's sighting would be the first time the species has shown up on Sunshine Coast sand in over a decade. Which brings us to the big question: what on earth was the seal doing here?
It's a tough question to answer without more information about this particular individual. Krause notes that in other similar species, migrations like this tend to occur among exploration-hungry young males, or animals that are sick and disoriented. Substantial environmental changes in factors such as water temperature or food distribution can also play a part.
In fact, a real leopard seal turned up on Queensland's Fraser Island back in 2014. That animal was both emaciated and badly injured, so officials made the decision to euthanise it.
"In this case, the animal looks healthy," says Krause. "And it definitely appears to be an adult male, so explanations one and two are likely out. I'd bet that climate shifts, unusual storms, or follow-on effects from large-scale oceanographic patterns in the Pacific might have played a role."
Interestingly, these animals have popped up in even stranger places: vagrant subantarctic fur seals have hauled out in both Madagascar and Mauritius.
"It'll be interesting to see if any others show up in the coming winter," says Krause.
If you live in the Queensland region and have intel on the current whereabouts of this seafaring explorer, let us know in the comments below.
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Top header image: A true leopard seal, Gilad Rom/Flickr
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